CN1765147A - Radio base station system, channel allocation method and channel allocation program - Google Patents

Abstract

A frame synchronization part (11b) of a slave base station (1b) synchronizes the frame thereof with the frame of a master base station (1a). A reception control slot setting control part (12b) sets a predetermined reception slot in the frame of the slave base station (1b), which has the same timing as the reception control slot in the frame of the master base station (1a), to the reception control slot. A reception level acquiring part (13a,13b) of each base station (1a,1b), when receiving a link channel establishment request message by use of the reception control slot, acquires the reception level of the slot. A call channel assignment control part (20a,20b) assigns, in accordance with a call channel assignment instruction, a call channel to a mobile station that has transmitted the link channel establishment request message to predetermined transmission and reception slots in the frame.

Description

Radio base station system, channel allocation method and channel allocation program

technical field

The present invention relates to a radio base station system, a channel allocation method of the radio base station system, and a channel allocation program of the radio base station system, in particular to a system consisting of a master base station and multiple slave base stations connected to the master base station through cables A radio base station system, a channel allocation method of the radio base station system, and a channel allocation program of the radio base station system.

Background technique

In radio base stations such as PHS, TDMA/TDD is used for communication. In this TDMA/TDD scheme, one frame is composed of four pairs of uplink and downlink time slots. Usually, one pair of time slots among the four pairs of time slots is assigned a control channel, and the remaining three pairs of time slots are assigned communication channels. The control channel is denoted by "C" and the communication channel is denoted by "T". A normal frame of a radio base station is constituted by a 1C3T frame.

However, Japanese Laid-Open Patent Publication No. 2000-102056 discloses a radio base station system composed of a master base station and slave base stations. The frame of the primary base station is composed of a normal frame, that is, 1C3T. The control channel of the master base station is shared by the master base station and the slave base station. Therefore, all 4 pairs of time slots in the secondary base station are allocated communication channels. As a result, a normal frame of the slave base station is constituted by a 4T frame. Therefore, the frame structure of the entire radio base station is 1C7T.

In a radio base station system composed of such a master base station and slave base stations, it is not necessary to allocate a control channel to a frame of the slave base station, so that the number of assignable communication channels can be increased.

However, when the mobile station makes an outgoing call to the radio base station system, the master base station receives link channel establishment request information from the mobile station, and assigns a communication channel to the frame of the master base station or the slave base station.

When the communication channel is assigned to the frame of the primary base station, there is no problem since the base station that received the link channel establishment request is the same base station as the base station to which the communication channel is assigned.

However, when the communication channel is assigned to the frame of the subordinate base station, the base station that receives the link channel establishment request is different from the base station to which the communication channel is assigned. In this case, there are the following problems.

The radio wave condition of the master base station is suitable for communication with the mobile station. Even if the master base station can accept the link channel establishment request, the radio wave condition of the slave base station is not suitable for communication with the mobile station. The mobile station and There are also cases where appropriate information exchange cannot be performed between the slave base stations. In this case, outgoing calls from the mobile station will fail.

Therefore, it is an object of the present invention to provide a radio base station system which easily and successfully completes an outgoing call from a mobile station in a radio base station system composed of a master base station and a plurality of slave base stations, a channel allocation method of the radio base station system, and the radio base station system. Channel allocation procedures for base station systems.

disclosure of invention

In order to solve the above-mentioned problems, the radio base station system of the present invention is composed of a master base station, a plurality of slave base stations, and a control device for controlling the master base station and the slave base stations. Frame synchronizing part, and the predetermined receiving time slot in the frame of this office with the same timing as the receiving control time slot in the frame of the main base station is set as the time slot setting part for receiving the control time slot; all base stations include: When receiving the link channel establishment request information in the control time slot for reception that has been set, the reception level acquisition part that obtains the reception level of the time slot, and according to the communication channel allocation instruction, the predetermined time for transmission and reception in the frame The communication channel allocating part that distributes the communication channel between the mobile stations that send the link channel establishment request information in the slot; the control device includes receiving the reception level from each base station, specifying the base station with the maximum reception level, and transmitting the communication channel to the specific base station Allocation indication parts for allocation indications.

Preferably, the communication channel allocating unit of the subordinate base station allocates a communication channel to the receiving time slot satisfying the predetermined condition when there is a receiving time slot satisfying the predetermined condition other than the predetermined receiving time slot, and there is no receiving time slot satisfying the predetermined condition. , assign a communication channel to a predetermined time slot for reception.

Preferably, the subordinate base station also includes that after assigning the communication channel to the predetermined receiving time slot, when a receiving time slot meeting a predetermined condition is generated in a receiving time slot other than the predetermined receiving time slot, the time slot of the allocated communication channel is converted into A communication channel switching unit for receiving time slots satisfying a predetermined condition.

The channel allocation method of the present invention is a channel allocation method of a radio base station system composed of a master base station, multiple slave base stations, and control devices for controlling the master base station and the slave base stations, including: the slave base station makes the frame of the master base station and the frame of the local office The step of keeping the frame synchronous; the step in which the slave base station sets the scheduled receiving time slot in the frame of the local office with the same timing as the receiving control time slot in the frame of the master base station as the step of receiving the control time slot; When receiving link channel establishment request information in a given control time slot for receiving, the step of obtaining the receiving level of the time slot; the control device receives the receiving level from each base station, specifies the base station with the largest receiving level, and for a specific The step of the base station transmitting the communication channel allocation instruction; the step of the base station receiving the communication channel allocation instruction assigning the scheduled transmission and reception time slots in the frame and the communication channel between the mobile stations sending the link channel establishment request information.

Preferably, in the step of allocating the communication channel of the subordinate base station, when there is a receiving time slot satisfying the predetermined condition other than the predetermined receiving time slot, the communication channel is allocated to the receiving time slot satisfying the predetermined condition, and there is no receiving time slot satisfying the predetermined condition. When time slots are used, communication channels are assigned to predetermined receiving time slots.

Preferably, the channel allocation method further includes that after the sub-base station allocates the communication channel to the predetermined receiving time slot, when a receiving time slot meeting a predetermined condition is generated in a receiving time slot other than the predetermined receiving time slot, the assigned communication channel The step of converting a time slot into a receiving time slot satisfying a predetermined condition.

The channel assignment program of the present invention is the channel assignment program of the radio base station system that is constituted by a master base station, a plurality of slave base stations, and control devices for controlling the master base station and the slave base stations, and the computer is made to perform the following steps: the slave base station makes the frame of the master base station The step of maintaining synchronization with the frame of the local station; the step of setting the predetermined receiving time slot in the frame of the station at the same timing as the receiving control time slot of the main base station by the slave base station as the step on the receiving control time slot; all When the base station receives the link channel establishment request information in the set reception control time slot, the step of obtaining the reception level of the time slot; the control device receives the reception level from each base station, and specifies the base station with the highest reception level , the step of transmitting a communication channel allocation instruction for a specific base station; the step of the communication channel between the base station receiving the communication channel allocation instruction allocating the predetermined transmission and reception time slots in the frame and the mobile station sending the link channel establishment request information .

Preferably, in the step of allocating the communication channel of the subordinate base station, when there is a receiving time slot satisfying the predetermined condition other than the predetermined receiving time slot, the communication channel is allocated to the receiving time slot satisfying the predetermined condition, and there is no receiving time slot satisfying the predetermined condition. When a slot is used, a communication channel is assigned to a predetermined receiving time slot.

Preferably, the channel allocation program causes the computer to further execute the slave base station to allocate the communication channel when a receiving time slot satisfying a predetermined condition occurs in a receiving time slot other than the predetermined receiving time slot after the communication channel is allocated to the predetermined receiving time slot. The step of converting a time slot into a receiving time slot satisfying a predetermined condition.

Therefore, the radio base station system, channel allocation method, and channel allocation program of the present invention can easily and successfully complete outgoing calls from mobile stations.

A brief description of the drawings

FIG. 1 is a functional block diagram showing the configuration of a radio base station system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a frame structure in the TDMA/TDD mode.

FIG. 3 is a schematic diagram of the frame structure of the primary base station and the secondary base station.

Fig. 4 is a schematic diagram of the data format of link channel establishment request information.

FIG. 5A is a schematic diagram of an example of allocating communication channels to frames of the master base station.

FIG. 5B is a schematic diagram of an example of allocating a communication channel to a frame of a secondary base station.

FIG. 5C is a schematic diagram of another example of allocating a communication channel to a frame of a secondary base station.

Fig. 6 is a schematic diagram of a data format of link channel allocation information.

FIG. 7 is a schematic diagram of a data format of link channel allocation rejection information.

FIG. 8 is a schematic diagram of an example of switching the intra-frame communication channel of the slave base station.

FIG. 9 is a schematic diagram of the data format of the communication channel switching indication information.

Fig. 10 is a flowchart showing the operation procedure of the call channel allocation process.

Fig. 11 is a flowchart showing the operation procedure of the call channel switching process.

Best Mode for Carrying Out the Invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The terms and processing procedures used in this embodiment are basically in accordance with "Standard Specifications for Second Generation Cordless Telephone System" RCRSTD-28.

FIG. 1 is a functional block diagram showing the configuration of a radio base station system according to an embodiment of the present invention. Please refer to FIG. 1 , the radio base station system includes a master base station 1 a , a slave base station 1 b and a control device 30 . The master base station 1a and the control device 30 and the slave base station 1b and the control device 30 are connected by cables.

The master base station 1a includes a radio unit 2a, a signal processing unit 3a, a modem unit 4a, and a main control unit 5a. The slave base station 1b includes a radio unit 2b, a signal processing unit 3b, a modem unit 4b, and a slave control unit 5b.

The radio unit 2a includes a reception unit 8a, a transmission unit 9a, and an RSSI detection unit 10a.

The receiving unit 8a down-converts a high frequency signal (RF signal) received from an antenna selected by selective diversity reception into an intermediate frequency signal (IF signal) and amplifies it to a predetermined voltage level.

The transmitter 9a up-converts an intermediate frequency signal (IF signal) into a high frequency signal (RF signal), amplifies it to a predetermined voltage level, and outputs it to an antenna selected for diversity transmission.

The RSSI (Received Signal Strength Indicator) detection unit 10a detects the reception level of the received RF signal, and outputs it to the main control unit 5a.

The modem unit 4a includes a modulation unit 7a and a demodulation unit 6a. The modulation unit 7 a performs modulation processing of the π/4 shift QPSK method on the transmission signal, and outputs the modulated signal to the signal processing unit 6 . The demodulation unit 6a performs demodulation processing of the π/4 shift QPSK method on the reception signal processed by the signal processing unit 6, and outputs the demodulated information to the main control unit 5a.

The signal processing unit 3a executes signal processing such as synchronization processing, time division processing, scrambling, and descrambling in accordance with the PHS standard.

The signal processing unit 3a performs time division processing according to the TDMA/TDD (Time Division Multiple Access/Time Division Duplex) method. Fig. 2 shows the frame structure of the TDMA/TDD scheme. As shown in the figure, in the TDMA/TDD scheme, one frame consists of four pairs of downlink (radio base station → mobile terminal) and uplink (mobile terminal → radio base station) time slots. The length of each slot is 625 μsec and 240 bits, and the length of one frame is 5 msec and 8 slots. From the perspective of the base station, the four downlink time slots are used for transmission, and the four uplink time slots are used for reception.

The 4 pairs of time slots are allocated to control channel (Control Channel: hereinafter referred to as CCH) or call (information) channel (Traffic Channel: hereinafter referred to as TCH). The time slot allocated to CCH is called control time slot, and the time slot allocated to TCH is called talk time slot. The CCH information is sent through the CCH, and the TCH information is sent through the TCH. CCH information is used to activate TCH to establish TCH.

The frequencies of these time slots are not necessarily the same. A frequency dedicated to control is used in the control slot, and a vacant frequency among a plurality of communication frequencies is used in the call slot.

Since the radio unit 2b, the signal processing unit 3b, and the modem unit 4b in the slave base station 1b respectively perform the same processes as the radio unit 2a, the signal processing unit 3a, and the modem unit 4a in the master base station 1a, these processes are not repeated. A description of the constituent elements.

Please refer to FIG. 1 again, the main control unit 5a includes a reception level acquisition unit 13a, a frame synchronization control unit 11a and a communication channel allocation control unit 20a. The slave control unit 5b includes a reception level acquisition unit 13b, a frame synchronization control unit 11b, a communication channel allocation control unit 20b, a reception control slot setting control unit 12b, and a communication channel switching control unit 15b.

The frame synchronization control unit 11a in the main control unit 5a controls the signal processing unit 3a to perform frame synchronization with other base stations. Each base station transmits CCH information at a frequency of 100 msec using downlink slot 1 for transmission shown in FIG. 2 . If the transmission timing of the CCH information is repeated among the base stations, the CCH information transmitted by the base stations will be interfered, and the mobile station will not be able to obtain correct CCH information. Therefore, each base station performs frame synchronization with other base stations at a predetermined cycle (for example, at a predetermined time of day). The frame synchronization control unit 11 a transmits the frame timing of its own station to the frame synchronization notification unit 33 of the control device 30 after performing frame synchronization with other base stations.

Fig. 3 shows the frame structure of the master base station and the slave base station in the link channel establishment phrase (phrase). As shown in the figure, the main base station 1a transmits CCH information every 100 msec (ie, 20 frames), and receives CCH information every 5 msec (ie, 1 frame).

Once the frame synchronization control unit 11b of the slave base station 1b receives the frame timing of the master base station 1a from the frame synchronization notification unit 33 of the control device 30, it will control the signal processing unit 3b so that the frame timing of the slave base station is synchronized with the frame timing of the master base station 1a. The timing is the same. When the frame synchronization with another base station has been established, the frame synchronization control unit 11b notifies the fact to the reception control slot setting control unit 12b.

When the reception control slot setting control unit 12b of the slave base station 1b receives a notification that the frame synchronization has been established from the frame synchronization control unit 11b, or receives a notification that the communication channel has been switched from the communication channel switching control unit 15, it will control the signal. The processing unit 3b sets, as shown in FIG. 3, a first reception slot which is a time slot with the same timing as the reception control slot of the main base station 1a, as the reception control slot. The slave base station 1b is different from the master base station 1a in that no control slot is set in the transmission slot.

The reception level acquisition unit 13a of the master base station 1a and the reception level acquisition unit 13a of the slave base station 1b perform the same processing. That is, the reception level acquisition units 13a, 13b acquire the demodulated data of the signal received in the first reception slot output from the demodulation units 6a, 6b, and check whether it is link channel establishment request information.

Fig. 4 shows the data format of link channel establishment request information. Please refer to the figure, the link channel establishment request information consists of transition response transient amplification (R), start symbol (SS), preamble (PR), unique word (UW), channel control (CI), base station identification code (CS -ID), mobile station identification code (PS-ID), information bit, error check bit (CRC).

Transient Response Transient Amplification (R) is a signal that smoothes the transition state of the rising and falling edges of the transmission signal. A start symbol (SS) is a signal indicating the start of a transmission signal. The preamble (PR) is a signal that generates a clock signal from a received signal and establishes bit synchronization between the base station and the mobile station. The Unique Word (UW) is a signal that establishes byte synchronization. The channel control (CI) indicates that the slot is used as an individual cell channel (SCCH). The base station identification code (CS-ID) is a code assigned to each base station. The mobile station identification code (PS-ID) is a code assigned to each base station. The type of information included in the information bit indicates that the information is link channel establishment request information. An error check bit (CRC) is a bit to detect an error based on a generator polynomial.

When the reception level acquisition part 13a, 13b obtains the link channel establishment request information, the reception level of the reception signal of the reception time slot after the next cycle is detected by the RSSI detection part 10a, 10b, and the received reception level The information is sent to the communication channel allocation instruction unit 31 of the control device 30 .

The communication channel allocation control unit 20a of the master base station 1a measures the interference levels of the second to fourth receiving slots in the frame when receiving a communication channel allocation instruction from the communication channel allocation instructing unit 31 of the control device 30.

If the minimum value of the interference level of the measured 2nd to 4th receiving time slots is below the predetermined threshold, the communication channel allocation control unit 20a will control the signal processing unit 3a to set the minimum interference level for the time slot (receiving time slot) slot) and the communication channel allocated to the transmission time slot paired with the time slot.

FIG. 5A is a schematic diagram of an example of frame allocation of communication channels to the primary base station. As shown in the figure, the communication channel is assigned to the fourth time slot of the frame of the master base station 1a.

When the minimum value of the measured interference levels of the second to fourth reception slots exceeds a predetermined threshold, the communication channel allocation control unit 20a determines that allocation is not possible.

The communication channel allocation control unit 20b of the slave base station 1b measures the interference levels of the second to fourth receiving slots in the frame when receiving a communication channel allocation instruction from the communication channel allocation instruction unit 31 of the control device 30.

If the measured minimum values of the interference levels of the 2nd to 4th receiving time slots are below the predetermined threshold, the call channel allocation control unit 20b will control the signal processing unit 3b to set the minimum interference level for the time slots (receiving time slots) slot) and the communication channel allocated to the transmission time slot paired with the time slot.

FIG. 5B is a schematic diagram of an example of allocating a communication channel to a frame of a secondary base station. As shown in the figure, the communication channel is assigned to the second slot of the frame of the slave base station 1b.

When the measured minimum values of the interference levels of the second to fourth receiving slots exceed a predetermined threshold, the traffic channel allocation control unit 20b measures the interference level of the first receiving slot.

If the measured interference level of the first receiving time slot is below a predetermined threshold, the communication channel allocation control unit 20b controls the signal processing unit 3b to allocate a communication channel to the first time slot (the receiving time slot and the transmitting time slot). .

FIG. 5C is a schematic diagram of another example of allocating a communication channel to a frame of a secondary base station. As shown in the figure, the communication channel is assigned to the first slot of the frame of the slave base station 1b. Accordingly, the reception control slot disappears in the frame of the slave base station 1b.

When the measured interference level of the first receiving slot exceeds a predetermined threshold, the communication channel allocation control unit 20b determines that allocation is not possible.

When the communication channel assignment control unit 20b has allocated the communication channel, it notifies the assignment result notification unit 32 of the control device 30 of the assigned communication channel and the assigned time slot number.

When the communication channel allocation control unit 20b determines that the communication channel cannot be allocated, it notifies the allocation result notification unit 32 of the control device 30 that it is determined that the communication channel cannot be allocated.

When the communication channel is allocated by the local office and the allocation result notification unit 32 of the control device 30 receives the time slot number and the allocation of the communication channel from the slave base station 1b, the communication channel allocation control unit 20a controls the signal processing unit 3a, 3b, Send link channel allocation information.

Fig. 6 is a schematic diagram of a data format of link channel allocation information. Referring to the figure, link channel allocation information consists of transient response amplification (R), start symbol (SS), preamble (PR), unique word (UW), channel control (CI), base station identification code (CS-ID ), mobile station identification code (PS-ID), information bit, error check bit (CRC). Transient Response Transient Amplification (R), Start Symbol (SS), Preamble (PR), Unique Word (UW), Channel Control (CI), Base Station Identification Code (CS-ID), Mobile Station Identification Code (PS-ID ), the error check bit (CRC) is consistent with the configuration in the link channel establishment request message.

The type of information contained in the information bit indicates that the information is link channel allocation information. The slot number indicates the slot number to which the communication channel is allocated. The slot numbers of the second to fourth slots in the frame of the master base station 1a are 1 to 4, respectively, and the slot numbers of the first to fourth slots in the frame of the slave base station 1b are 5 to 8, respectively.

When it is judged that the communication channel cannot be allocated in the local office and the allocation result notification unit 32 of the control device 30 receives a notification that the communication channel cannot be allocated in the slave base station 1b, the communication channel allocation control unit 20a will control the signal processing units 3a, 3b, Send link channel allocation rejection information.

FIG. 7 is a schematic diagram of a data format of link allocation rejection information. Refer to the figure, the link channel assignment rejection information consists of Transition Response Transient Amplification (R), Start Symbol (SS), Preamble (PR), Unique Word (UW), Channel Control (CI), Station Identification Code (CS -ID), mobile station identification code (PS-ID), information bit, error check bit (CRC). Transient Response Transient Amplification (R), Start Symbol (SS), Preamble (PR), Unique Word (UW), Channel Control (CI), Base Station Identification Code (CS-ID), Mobile Station Identification Code (PS-ID ), the error check bit (CRC) is consistent with the configuration in the link channel establishment request message.

The type of information included in the information bit indicates that the information is link allocation rejection information.

When the communication channel is assigned to the first time slot, if the minimum value of the interference level of the second to fourth reception time slots is below a predetermined threshold, the communication channel switching control unit 15b of the slave base station 1b controls the signal processing unit 3b. While switching the communication channel of the time slot (receiving time slot) with the smallest interference level and the transmission time slot paired with this time slot, notify the reception control slot setting control unit 12b that the communication channel has been switched. Purpose.

FIG. 8 is a schematic diagram of an example of switching the intra-frame communication channel of the slave base station. As shown in the figure, the communication channel allocated to the first slot of the frame of the slave base station 1b is allocated to the third slot by switching. Also, the first reception slot is reset as a reception control slot.

When the communication channel is switched, the communication channel switching control unit 15b controls the signal processing unit 3b to transmit communication channel switching instruction information.

FIG. 9 is a schematic diagram of the data format of the communication channel switching indication information. Refer to the figure, the talk channel change indication information consists of Transition Response Transient Amplification (R), Start Symbol (SS), Preamble (PR), Unique Word (UW), Channel Control (CI), SA, Information Bit, Error A check bit (CRC) is formed.

Transient Response Transient Amplification (R), Start Symbol (SS), Preamble (PR), Unique Word (UW), Channel Control (CI), Error Check Bit (CRC) are consistent with the configuration in the link channel establishment request message .

Channel control (CI) indicates that the time slot is used as a low-speed incidental control channel (SACCH), and SA indicates a low-speed incidental control signal.

The type of information contained in the information bit indicates that the information is the communication channel switching indication information. The base station identification code (CS-ID) included in the information bits is a code assigned to each base station. The time slot number included in the information bit indicates the time slot number to which the communication channel is allocated.

The control device 30 includes a communication channel allocation instruction unit 31 , an allocation result notification unit 32 , and a frame synchronization control unit 33 .

The communication channel allocation instructing unit 31 obtains the reception level from the base station. When the communication channel allocation instructing unit 31 obtains the reception level from only one base station, it selects that base station as the communication base station. When the communication channel allocation instructing unit 31 acquires the reception levels from two base stations, it selects the base station with the highest reception level as the communication base station. The communication channel allocation instructing unit 31 transmits a communication channel allocation instruction to the communication channel allocation control unit of the selected base station.

When the allocation result notification unit 32 receives a notification of the allocated communication channel and the assigned time slot number from the communication channel allocation control unit 20b, or receives a notification of the determination that the communication channel cannot be allocated from the communication channel allocation control unit 20b, The notified information is transferred to the communication channel allocation control unit 20a.

The frame synchronization notification unit 33 notifies the frame synchronization control unit 11b of the slave base station 1b of the timing of the frame received from the frame synchronization control unit 11a of the master base station 1a.

(communication channel assignment action)

Fig. 10 is a flowchart showing the operation procedure of the communication channel allocation process executed by software in the radio base station system according to the embodiment of the present invention. The radio base station system reads and executes a program including each step of the flowchart from a memory (not shown). The program can be installed externally.

First, the frame synchronization control unit 11 a of the main base station 1 a notifies the frame synchronization notification unit 33 of the control device 30 of the frame timing of the main base station 1 a. The frame synchronization notification unit 33 of the control device 30 notifies the frame synchronization control unit 11b of the slave base station 1b of the timing of the frame received from the frame synchronization control unit 11 of the master base station 1a. The frame synchronization control unit 11b of the slave base station 1b controls the signal processing unit 3b to synchronize the frame timing of its own station with the frame timing of the master base station 1a (step 401).

The reception control slot allocation control unit 12b of the slave base station 1b controls the signal processing unit 3b to allocate the first reception slot in the frame to the reception control slot (step S402).

The reception level acquisition units 13a, 13b of the master base station 1a and the slave base station 1b acquire the demodulated data of the signal received in the first reception slot output from the demodulation unit 6, and check whether it is link channel establishment request information ( Step S403).

When the reception level acquisition part 13a, 13b obtains the link channel establishment request information, the RSSI detection part 10a, 10b will detect the reception level of the reception signal of the receiving time slot in the next cycle, and transmit the obtained reception level to the communication channel allocation instructing unit 31 of the control device 30 (step S404).

When the communication channel allocation instructing unit 31 of the control device 30 obtains the reception level from only one base station, it selects that base station as the communication base station. When the communication channel allocation instructing unit 31 of the control device 30 obtains reception levels from two base stations, the base station with the highest reception level is selected as the communication base station. The communication channel allocation instructing unit 31 transmits a communication channel allocation instruction to the communication channel allocation control unit of the selected base station (step S405).

When the communication channel allocation control unit 20a of the main base station 1a receives the communication channel allocation instruction from the communication channel allocation instruction unit 31 of the control device 30 (step S406), it measures the interference levels of the second to fourth receiving time slots in the frame, If the measured minimum values of the interference levels of the second to fourth receiving time slots are below the predetermined threshold (step S407), the signal processing unit 3a will be controlled so that the time slot with the smallest interference level (receiving time slot) And the communication channel is assigned to the transmission time slot paired with the time slot (step S408).

On the other hand, when the minimum value of the measured interference levels of the second to fourth receiving slots exceeds a predetermined threshold (step S407), the communication channel allocation control unit 20a determines that allocation is not possible (step S409).

When the communication channel allocation control unit 20b of the slave base station 1b receives the communication channel allocation instruction from the communication channel allocation instruction unit 31 of the control device 30 (step S406), it measures the interference levels of the second to fourth receiving time slots in the frame, If the measured minimum values of the interference levels of the second to fourth receiving time slots are below the predetermined threshold (step S410), the signal processing unit 3b is controlled to set the minimum interference level for the time slot (receiving time slot) And the communication channel is assigned to the transmission time slot paired with the time slot. When the communication channel allocation control unit 20b has allocated the communication channel, it notifies the allocation result notification unit 32 of the control device 30 of the assigned communication channel and the assigned time slot number (any one of 2 to 4). The allocation result notification unit 32 of the control device 30 notifies the communication channel allocation control unit 20a of the main base station 1a of the information that these notifications have been received (step S411).

When the minimum value of the measured interference levels of the second to fourth receiving time slots exceeds a predetermined threshold (step S410), the communication channel allocation control unit 20b measures the interference level of the first receiving time slot. When the interference level of 1 receiving slot is below a predetermined threshold (step S412), the signal processing unit 3b is controlled to allocate a communication channel to the first slot (the receiving slot and the transmitting slot). When the communication channel allocation control unit 20b allocates the communication channel, it notifies the allocation result notification unit 33 of the control device 30 of the number of the allocated communication channel and the assigned slot number (=1). The allocation result notification unit 33 notifies the communication channel allocation control unit 20a of the primary base station 1a of the information of these notifications (step S413).

When the measured interference level of the first receiving slot exceeds a predetermined threshold (step S412), the communication channel allocation control unit 20b determines that allocation is not possible. When the communication channel allocation control unit 20b determines that the communication channel cannot be allocated, it notifies the allocation result notification unit 33 of the control device 30 that it is determined that the communication channel cannot be allocated. The allocation result notification unit 33 notifies the communication channel allocation control unit 20a of the primary base station 1a of the information obtained by these notifications (step S414).

When the communication channel is assigned by the local office and the allocation result notification unit 32 of the control device 30 receives the assignment of the communication channel from the slave base station 1b and the allocated time slot number, the communication channel allocation control unit 20a will control the signal processing unit 3a, and Send link channel allocation information (step S415).

When it is judged that the communication channel cannot be allocated in the local office, and when receiving a notification that the allocation result notification unit 33 of the control device 30 determines that the communication channel cannot be allocated from the slave base station 1b, the communication channel allocation control unit 20a will control the signal processing unit 3a, and transmit the chain The channel allocation rejection information (step S416).

(Channel switching action)

11 is a flowchart showing the operation procedure of the communication channel switching process executed by software in the radio base station system according to the embodiment of the present invention. The radio base station system reads and executes a program including each step of the flowchart from a memory (not shown). The program can be installed externally.

In the case of assigning a communication channel to the first time slot (step S51), if the minimum value of the interference level of the second to fourth receiving time slots is below a predetermined threshold (step S52), the communication channel of the slave base station 1b is switched to The control unit 15b will control the signal processing unit 3b to switch the time slot (receiving time slot) with the smallest interference level and the communication channel of the transmission channel paired with this time slot, and set the control unit to the receiving control time slot. 12b notifies the purpose of switching the call channel (step S53).

The reception control slot allocation control unit 12b of the slave base station 1b controls the signal processing unit 3b to allocate the first reception slot in the frame to the reception control slot (step S54).

When the communication channel is switched, the communication channel switching control unit 15b controls the signal processing unit 3b to transmit communication channel switching instruction information (step S55).

As described above, according to the radio base station system of this embodiment, the link channel establishment request is acquired at two places, the master base station 1a and the slave base station 1b, and the frame of the base station whose reception level is the maximum value at the time of acquiring the link channel establishment request is The communication channel is allocated, so the base station receiving the link channel establishment request and the base station allocated the communication channel are the same, and it is easy to successfully complete the outgoing call from the mobile station.

(Modification)

The present invention is not limited to the above-described embodiments, and includes, for example, the following modified examples.

(1) Control slot for reception

In the embodiment of the present invention, the first time slot of the receiving time slots in the master base station 1a and the slave base station 1b is set as the receiving control time slot, but it is not limited to this, as long as it is the same timing, it can be the first time slot Any one of the 2nd to 4th time slots.

(2) Allocation of communication channels to the first time slot

In the embodiment of the present invention, when the communication channel cannot be allocated to the second to fourth time slots in the frame of the slave base station 1b, the allocation of the communication channel to the first time slot is allowed, but it is also possible to absolutely prohibit the allocation of the first time slot. call channel.

All of the embodiments disclosed this time are just examples, and it should be understood that they are not limited thereto. The scope of the present invention is shown not by the above-described description but by the claims, and all changes within the meaning equivalent to the scope of the claims and within the scope are included in the scope of the present invention.

As described above, in the present invention, the slave base station keeps the frame of the main base station and the frame of the own station synchronized, and sets a predetermined receiving time slot in the frame of the own station with the same timing as the receiving control slot in the frame of the master base station as the receiving time slot. When all the base stations receive the link channel establishment request information in the set receiving control time slot, they obtain the receiving level of the time slot, and according to the communication channel allocation instruction, send and receive signals scheduled in the frame. The control device receives the reception level from each base station using the communication channel between the mobile stations that allocate time slots and transmit link channel establishment request information, specifies the base station with the highest reception level, and transmits a communication channel allocation instruction to the specified base station.

Therefore, the radio base station system, channel allocation method and channel allocation program of the present invention can easily and successfully complete outgoing calls from mobile stations.

Industrial Utilization Possibility

In a radio base station system composed of a master base station and a plurality of slave base stations, it is particularly effective for a radio base station system such as a PHS because it is easy to make a successful call.

Claims (9)

1. A radio base station system, comprising a master base station (1a), a plurality of slave base stations (1b) and a control device (30) for controlling the master base station (1a) and the slave base stations (1b), The slave base station (1b) includes: A frame synchronization unit (11b) for keeping the frame of the main base station (1a) and the frame of the local office in sync, A time slot setting part (12b) that sets a predetermined receiving time slot in a frame of the local office with the same timing as the receiving control time slot in the main base station (1a) as the receiving control time slot; All base stations (1a, 1b) include: When receiving link channel establishment request information in the set reception control slot, receiving level acquisition means (13a, 13b) for acquiring the reception level of the slot, According to the communication channel allocation instruction, the communication channel allocation means (20a, 20b) that allocates the communication channel between the mobile stations that send the link channel establishment request information to the predetermined sending and receiving time slots in the frame; The control device (30) includes: An allocation instructing unit (31) that receives a reception level from each base station (1a, 1b), specifies a base station with the highest reception level, and transmits a call channel allocation instruction to the specified base station. 2. The radio base station system according to claim 1, characterized in that: the communication channel allocation part (20b) of the subordinate base station (1b) has a receiving time slot satisfying a predetermined condition other than the predetermined receiving time slot When there is no receiving time slot satisfying the predetermined condition, the communication channel is allocated to the predetermined receiving time slot. 3. The radio base station system as claimed in claim 2, characterized in that: said subordinate base station (1b) further comprises: after allocating a communication channel to said predetermined receiving time slot, receiving signals other than said predetermined receiving time slot A communication channel conversion unit (15b) for converting the time slot allocated to the communication channel into a reception time slot satisfying the predetermined condition when a reception time slot satisfying a predetermined condition is generated among the use time slots. 4. A channel allocation method for a radio base station system, the radio base station system comprising a master base station (1a), a plurality of slave base stations (1b) and a control device (30 for controlling the master base station (1a) and the slave base stations (1b) ), the channel allocation method includes: A step in which the slave base station (1b) keeps the frame of the master base station (1a) and the frame of the local office synchronous; A step in which the slave base station (1b) sets a predetermined receiving time slot in the frame of the local office at the same timing as the receiving control time slot in the frame of the master base station (1a) as the receiving control time slot; When all the base stations (1a, 1b) receive the link channel establishment request information in the set reception control time slot, the step of obtaining the reception level of the time slot; The control device (30) receives the reception level from each base station (1a, 1b), specifies the base station with the highest reception level, and transmits a call channel allocation instruction to the specific base station; The step of allocating the communication channel between the mobile station and the mobile station sending the link channel establishment request information to the scheduled transmission and reception time slots in the frame by the base station receiving the communication channel allocation instruction. 5. The channel allocation method according to claim 4, characterized in that: in the step of allocating the communication channel of the subordinate base station (1b), when there is a receiving time slot satisfying a predetermined condition other than the predetermined receiving time slot , allocating the communication channel to the reception time slot satisfying the predetermined condition, and allocating the communication channel to the predetermined reception time slot when there is no reception time slot satisfying the predetermined condition. 6. channel assignment method as claimed in claim 5, is characterized in that described channel assignment method also comprises: After the slave base station (1b) allocates a communication channel to the predetermined receiving time slot, when a receiving time slot satisfying a predetermined condition occurs in receiving time slots other than the predetermined receiving time slot, the allocated A step of converting the time slot of the communication channel into a receiving time slot satisfying the predetermined condition. 7. A channel allocation program for a radio base station system, the radio base station system comprising a master base station (1a), a plurality of slave base stations (1b) and a control device (30) for controlling the master base station (1a) and the slave base stations (1b) ), the channel allocation program makes the computer perform the following steps: A step in which the slave base station (1b) keeps the frame of the master base station (1a) and the frame of the local office synchronous; A step in which the slave base station (1b) sets a predetermined receiving time slot in the frame of the local office at the same timing as the receiving control time slot in the frame of the master base station (1a) as the receiving control time slot; When all the base stations (1a, 1b) receive the link channel establishment request information in the set reception control time slot, the step of obtaining the reception level of the time slot; The control device (30) receives the reception level from each base station (1a, 1b), specifies the base station with the highest reception level, and transmits a call channel allocation instruction to the specific base station; The step of allocating the communication channel between the mobile station and the mobile station sending the link channel establishment request information to the scheduled transmission and reception time slots in the frame by the base station receiving the communication channel allocation instruction. 8. The channel allocation program according to claim 7, wherein in the step of allocating the communication channel of the slave base station (1b), when there is a receiving time slot satisfying a predetermined condition other than the predetermined receiving time slot , allocating the communication channel to the reception time slot satisfying the predetermined condition, and allocating the communication channel to the predetermined reception time slot when there is no reception time slot satisfying the predetermined condition. 9. channel assignment program as claimed in claim 8, also makes computer carry out the following steps: After the slave base station (1b) allocates a communication channel to the predetermined receiving time slot, when a receiving time slot satisfying a predetermined condition occurs in receiving time slots other than the predetermined receiving time slot, the allocated A step of converting the time slot of the communication channel into a receiving time slot satisfying the predetermined condition.

Images